1. Field of the Invention
The present invention relates to a semiconductor packaging device.
2. Description of the Related Art
Conventional quad flat pack (QFP) method and pin-grid array (PGA) method for packaging integrated circuits cannot meet practical need as the functions of the integrated circuits have become more and more complicated while the integration level of the circuits become higher and higher. Ball-grid array integrated circuit (BGA IC) packaging method is one of the newly developed methods for ICs with a quantity of pins and is suitable for packaging integrated circuits of ultra-large scale integration (ULSI) produced by submicron resolution.
Typically, a mold is put on top of a BGA IC, and molten liquid plastic material (i.e., a package encapsulant) is then poured into the mold to completely enclose the integrated circuit chips on the substrate to thereby provide a completely air tight seal for the integrated circuit chips. The BGA IC is removed from the mold after the plastic material is hardened. A subsequent trim work is carried out on an area adjacent to a mold gate of the mold to remove the residual plastic material in a pouring channel of the mold.
In the above-mentioned packaging method for BGA ICs, a metallic plate is provided on the substrate and includes a metallic surface formed by deposition. When the substrate is covered by the mold, the metallic surface is located below the pouring channel of the mold. The metallic surface may serve as an isolation layer between the substrate and the pouring channel to provide an increased degating ability. More specifically, when removing the substrate from the mold, the metallic surface allows the package encapsulant residued in the pouring channel to be easily degated from the substrate. Thus, the residual on the packaged IC can be easily trimmed. Nevertheless, in addition to an increased cost, the metallic plate having the metallic surface occupies a certain space and thus might result in an increase in the product defective index.
The present invention is intended to provide a packaging device which mitigates and/or obviates the above problems.